Seagull Caliber ST1902 Watch Movement

Manufacturer	Seagull
Caliber Number	ST1902, ST-1902, ST19, 1902
Based On	Venus 175
Movement Type	Mechanical chronograph, manual-wind
Lignes	13.75”’
Diameter	31.3mm
Height	6.25mm
Jewels	22
Beats per hour	21,600 vph
Power Reserve	~42 hours (also seen reports of 51 hours)
Anti-Shock System	Incabloc
Chronograph System	Column Wheel
Hand-Windable?	Yes
Hacking Seconds?	No
Functions	Central hours, central minutes, small seconds at 9:00, 30 min chronograph subdial at 3:00, 12 hour subdial at 6:00
Country of Manufacture	China
Known Models	Invicta 5105 (Add your watch to the comments below…)

The Sea-Gull caliber ST1902 is a mechanical hand-wound chronograph movement. This caliber is known to be based off of the Venus caliber 175. At one point a legend was circulating around the internet claiming that this series of movements is not only based on Venus calibers, but also manufactured on the same machines. If anyone has actual proof of this claim, please share in the comments below.

Some of the topics covered in this caliber listing:

6:00 Subdial:

This movement is essentially a 2 subdial chronograph. The 6:00 subdial on the caliber ST1902 is often simply listed as a 12 hour subdial, causing confusion about the functionality. This is not a 12 hour totalizer subdial for the chronograph complication. It is a 12 hour hand that matches the main central hour hand.

Is ST1902 the same as ST19?

You may see the caliber number for this movement shortened to just ST19. This is accurate as the base caliber number, but it is not accurate when talking specifically about the ST1902. With ST19XX, the last two digits indicate different versions or complications added to the base ST19 (ST1901).